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Diagnostics of flare activity level from turbulence parameters of photospheric plasma

RHESSI/SOHO/TRACE Workshop. Pre-event Physics. December 8-11, 2004,Sonoma, California. Diagnostics of flare activity level from turbulence parameters of photospheric plasma. Abramenko, Valentyna Big Bear Solar Observatory of NJIT avi@bbso.njit.edu www.bbso.njit.edu/~avi. Introduction.

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Diagnostics of flare activity level from turbulence parameters of photospheric plasma

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  1. RHESSI/SOHO/TRACE Workshop Pre-event Physics December 8-11, 2004,Sonoma, California Diagnostics of flare activity level from turbulence parameters of photospheric plasma Abramenko, Valentyna Big Bear Solar Observatory of NJIT avi@bbso.njit.edu www.bbso.njit.edu/~avi

  2. Introduction A solar flare may be triggered as a chain reaction in a stressed coronal magnetic configuration. Flares occur as an unavoidable phase in evolution of a complex non-linear dynamical system of magnetized plasma (Parker 1988, a review by Charbonneau et al. 2001) The system extents from the convective zone to the corona through layers of plasma of different physical conditions. RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  3. Introduction Introduction RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  4. Introduction Essential properties of the photospheric plasma: Magnetized plasma in a turbulent state (Parker 1979), very intermittent (or, in other words, multifractal) medium (Lawrence et al. 1993, Abramenko et al. 2002), where the magnetic helicity may have an inverse cascade (Biskamp 1993) RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  5. Introduction Situation in the photosphere – flaring in the corona: Magnetic helicity transport in the photosphere (Rust & LaBonte 2003; Georgoulis, Rust & LaBonte – present meeting; Chae 2001; Romano – present meeting ). Statistical properties of electric currents, current helecity, magnetic flux, etc., derived from vector-magnetograms (Leka & Barnes 2004). Fractal dimensions of the photospheric magnetic fields (Tarbell et al. 1990; Balke et al. 1993; Meunier 1999; Ireland, Gallagher & McAteer 2003). RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  6. Introduction Situation in the photosphere – flaring in the corona: we propose to analyze 1. Distribution functions of the magnetic flux in elements of the magnetic field in active regions – present talk. (Abramenko & Longcope, ApJ, 2005) 2. Turbulence state of the photospheric magnetic field as derived from magnetic power spectrum – present talk. • Multifractality (intermittency) of the photospheric magnetic • fields – poster at the current meeting. • (Abramenko, Yurchyshyn, Wang, Goode, ApJ 577, 2002). RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  7. Distribution functions of the magnetic flux (Abramenko & Longcope, ApJ, 2005) Flare-quiet active region 0061 (C2) Flaring active region 9077 (X5.7) RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  8. Distribution functions of the magnetic flux (Abramenko & Longcope, ApJ, 2005) RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  9. Magnetic Power Spectrum: Flare-quiet active region 0061 Flaring active region 9077 RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  10. Flaring active region 9077 Magnetic Power Spectrum: Flare-quiet active region 0061 RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  11. Magnetic Power Spectrum: Flare-quiet emerging active region NOAA 9851 No X-ray flares during the passage across the disk RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  12. Magnetic Power Spectrum: Flaring emerging active region NOAA 0365 The most powerful flare during the passage across the disk: X3.6 RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  13. Flaring ARs 9773/M9.5 9077/X5.7 Jul 14 Flare-Quiet ARs Jul 13 9866/M5.7 0515/ - 9851/ - 0061/C2 0306/C1 Classical Kolmogorov Turbulence state Multifractality vs. Turbulence RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  14. Conclusions • Parameters of the turbulence state (the power index ) and of the structural organization (the distribution functions and the degree of multifractality, h) of the photospheric magnetic field correlate with flaring productivity of anactive region. RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  15. Conclusions • The turbulence state of the magnetic field at the phase of emergence seems to determine the ongoing flare productivity of an active region. • Further study on a large statistics is needed: the catalog of active regions observed in a high resolution mode by SOHO/MDI will be used • (Paolo Romano & Vasyl Yurchyshyn, www.bbso.njit.edu/~vayur/MDI_catalog.htm) RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  16. Calculation of Multifractality Structure functions were first introduced by Kolmogorov (1941). They were defined as statistical moments of the field increments: q is the order of a statistical moment, r is a separation vector, x is the current point on a magnetogram. <…> denotes the averaging over a magnetogram. q is a slope within the inertial range of scales. Classical Kolmogorov theory Refined Kolmogorov theory, multifractal structure RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  17. Calculation of Multifractality Historically accepted terminology:Analysis of Time series : intermittencyAnalysis of Spatial arrays : multifractality h(q)= d(q)/dq D(h(q))=2+qh(q)- (q) RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  18. Examples of different multifractality

  19. Calculation the Power Spectrum RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

  20. Calculation the Power Spectrum RHESSI/SOHO/TRACE Workshop/ WG 1: Pre-event Physics Dec 8-11, 2004, Sonoma, California

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